`this` pointer reference to normal vs virtual functions in superclass

Question

Consider the following code:

#include <cstdio>

struct Base {
  void callNormalFn() {
    normalFn();
  }
  void callVirtualFn() {
     virtualFn();
  }
  void normalFn() {
    printf("Base::normalFn\n");
  }
  virtual void virtualFn() {
    printf("Base::virtualFn\n");
  }
};

struct Derived : Base {
  void callNormalFn() {
    Base::callNormalFn();
  }
  void callVirtualFn() {
    Base::callVirtualFn();
  }
  void normalFn() {
    printf("Derived::normalFn\n");
  }
  virtual void virtualFn() {
    printf("Derived::virtualFn\n");
  }
};

int main() {
  Derived d = {};
  d.callVirtualFn();
  //=> Derived::virtualFn (why?)
  d.callNormalFn();
  //=> Base::normalFn (why?)
}

From c++ virtual function call without pointer or reference, my understanding says that:

• there is an implicit this pointer inside Base::callVirtualFn() or Base::callNormalFn(), e.g. this->virtualFn()
• the this pointer should point to the current object being operated on (in this case, the Derived class)

Why is then the this pointer resolves to different classes when calling normal vs virtual functions?